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SULPHONYLUREAS - a patient's guide


These medicines are used to treat Type 2 diabetes. This article details how they work and how they should be taken.


Glibenclamide: Gliben, Semi-Daonil, Daonil, Apo-Gliibenclamide

Glicazide: Diamicron

Glipizide: Glipid, Minidiab

Tolbutamide: Diatol

USE: Oral antidiabetes

This group of medicines are used in non-insulin dependent (Type II) diabetes. They work primarily by stimulating the release of insulin from the pancreas and enhancing its role in glucose transport.

Sulphonylureas are often prescribed in patients who are non-obese, because these drugs tend to encourage weight gain. They have a risk of hypoglycaemia (low sugar levels) which can be represented by tremor, sweating, anxiety, confusion, aggression, hunger, salivation, blurred vision, yawning, heaviness of legs etc.


  • Juvenile diabetes
  • Severe kidney and liver impairment (esp. elderly)
  • Gangrene, trauma, surgery
  • Diabetic coma, ketoacidosis
  • Pregnancy and breastfeeding

Side effects:

Generally mild stomach upset and headache.

Less commonly, skin rash and dizziness

Overdose leads to hypoglycaemia (low blood sugar - seek medical attention)


Hypoglycaemia (low sugar levels) can be enhanced by MAOIs, fibrates, antibacterials, and analgesics.

Oral contraceptives (the 'Pill'), corticosteroids, diuretics, alcohol, theophylline, thyroxine, phenytoin can effect glucose control (hyperglycaemia).

B-blockers can mask the effects of hypoglycaemia (low blood sugar).

Patient information:

  • Follow the instructions on the label of this medicine (don't exceed recommended dose)
  • Do not stop taking this medecine unless directed
  • Patient should be informed about diet, exercise and blood glucose monitoring
  • Food: can be taken after food, but best effect if half an hour before food.
  • Alcohol: restrict intake (risk of hyperglycaemia)
  • Hypoglycaemia (low blood sugar) can be controlled by taking carbohydrates (e.g. glucose tablets, sweet drink)
  • Other family members, partners should be informed about hypoglycaemia (warning signs and treatment)
  • Do not take other medicines unless directed by your doctor/pharmacist
  • Contact doctor or seek urgent medical help if side effects are severe (skin rash) or ongoing.

See also:

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